Thank you for being a Gates Notes Insider. I feel lucky that I get to connect with so many people like you. – Bill Gates

Not a Gates Notes Insider yet? Sign up

spacer

LOG IN

SIGN UP

EMAILPASSWORD

Forgot?

Log in

Or sign up with your social account:

Log in

Log in

Logout:

Become a Gates Notes Insider

Become a Gates Notes Insider

Join the Gates Notes community to access exclusive content, comment on stories, participate in giveaways, and more.

Already joined? Log in

spacer

LOG IN

SIGN UP

Sign up with your social account:

Sign up

Sign up

Or sign up with email:

TITLE

FIRST NAME

LAST NAME

EMAIL

This email is already registered. Enter a new email, try signing in or retrieve your password

PASSWORD

ADDRESS

Why are we collecting this information? Gates Notes may send a welcome note or other exclusive Insider mail from time to time. Additionally, some campaigns and content may only be available to users in certain areas. Gates Notes will never share and distribute your information with external parties.

ADDRESS LINE 1

Bill may send you a welcome note or other exclusive Insider mail from time to time. We will never share your information.

ADDRESS LINE 2

CITY

STATE / PROVINCE / REGION

ZIP / POSTAL CODE

COUNTRY

Sign up

Join the Gates Notes community to access exclusive content, comment on stories, subscribe to your favorite topics and more.We will never share or spam your email address. For more information see our Sign Up FAQ.By clicking "Sign Up" you agree to the Gates Notes Terms of Use / Privacy Policy.

Deactivating your account will unsubscribe you from Gates Notes emails, and will remove your profile and account information from public view on the Gates Notes. Please allow for 24 hours for the deactivation to fully process. You can sign back in at any time to reactivate your account and restore its content.

Deactivate My Acccount

Go Back

Your Gates Notes account has been deactivated.

Come back anytime.

Welcome back

In order to unsubscribe you will need to sign-in to your Gates Notes Insider account

Once signed in just go to your Account Settings page and set your subscription options as desired.

Sign In

Request account deletion

We’re sorry to see you go. Your request may take a few days to process; we want to double check things before hitting the big red button. Requesting an account deletion will permanently remove all of your profile content. If you’ve changed your mind about deleting your account, you can always hit cancel and deactivate instead.

Submit

Cancel

Thank You! Your request has been sent

Please complete your account verification. Resend verification email.

This verification token has expired.

Your email address has been verified. Update my profile.

Your account has been deactivated. Sign up to re-activate your account.

Reflections on the Reinventing the Toilet Challenge

I started thinking about the need for a new approach to toilets a few years ago, when I noticed on visits to some of the poorest slums that even in places with new community toilets they often weren’t used. Sometimes it was the smell that drove people away, or the fact that they were clogged up or poorly maintained. Other times it was because women didn’t feel safe using them. Often, the new toilets didn’t deal with human waste in a sanitary way, so they continued to spread diarrheal diseases that still kill more than a million children a year.

I realized we could apply the same kind of creative thinking and innovation to sanitation that we use to address other global health and development challenges. So, a year ago, the foundation invited eight universities to participate in a Reinvent the Toilet Challenge.

The criteria we set for the university researchers were pretty ambitious. We asked each team to develop a toilet that would destroy human waste or convert it into a valuable resource such as fuel or fertilizer. The toilet would have to operate “off the grid”—without connections to water, sewer, or electrical lines. The cost to operate it needed to be less than 5 cents per user, per day. And people would have to want to use it—ideally not only in poor countries, but wealthy ones too.

We gave each team about $400,000 and asked them to present the results of their work a year later. That happened last week at the foundation’s Reinvent the Toilet Fair. Given the boldness of the challenge and the limited time and money the teams had to work with, I wasn’t sure what to expect. After all, no one has invented a radically new toilet in 200 years.

The results were outstanding. It was impressive to see how each university team tackled the issues. Can you burn human excreta? Can you get energy out of it and how can you use or store that energy? How do you deal with smells as well as a flush toilet does? How do you make a complete toilet system simple, affordable, and something that doesn’t need a lot of maintenance? All of the prototypes still need more work, but the teams made fantastic progress and important contributions to the toilet of the future.

We awarded the first-place prize to the California Institute of Technology for their prototype of a self-contained, solar-powered toilet that produces enough power to run an electrochemical reactor that breaks down human waste and, in the process, generates hydrogen. A wastewater treatment system sanitizes the liquids, which can then be recycled for flushing or other purposes.

The second place prize went to Loughborough University in the United Kingdom. Their toilet uses a chemical process called hydrothermal carbonization to transform feces into a biological charcoal, which can be used as fertilizer, as a fuel source, or to power the toilet system. It also separates out minerals and clean water from feces and urine.

The third place prize was awarded to the University of Toronto in Canada for a toilet that dries and combusts solids and disinfects urine with a sand filter and ultra-violet light.

Creating affordable, sustainable, and scalable toilets that people will actually use is still several years away. But after last week, I am truly optimistic we can deliver a self-contained, zero-energy toilet that’s not dependent on traditional sanitation infrastructure.

It may seem funny to say I’m excited about toilets, but just as breakthroughs in new vaccines have saved millions of lives, and new seeds have helped farmers grow more sustainable and productive crops, the next-generation toilet will be an important contribution to helping the world’s poor live healthier, better lives.